These sentences have been changed into passive voice sentences by adding "let".

3. With Modal verbs:

The verbs can, could, may, might, and must are known modal verbs.
As per the following methods these sentences with these verbs are changed into passive voice.

Examples:

• You can take the book. (Active voice)
• The book can be taken by you. (Passive Voice).

• Everybody must obey the rules. (Active voice)
• The rules must be obeyed by everybody. (Passive Voice).

• They might have studied their lessons. (Active voice)
• Their lessons might have been studied by them. (Passive Voice).

• He may not accept this plan. (Active voice)
• This lesson may not be accepted by him. (Passive Voice).

4. Phrasal verbs:

Few verbs, with certain meanings are always used with prepositions.

In such situations the prepositions should not be omitted in the sentences.

Examples:

• We are looking at the game. (Active voice)
• The game is being looked at by us. (Passive Voice).

• The fire-brigade put out the fire. (Active voice)
• The fire was put out by the fire-brigade. (Passive Voice).

• The Government will set up a factory. (Active voice)
• A factory will be set up by the government. (Passive Voice).

5. With IT:

In few sentences, instead of a word or a phrase, a clause may be the object of a verb.

In such cases there are two ways of changing the sentences into the passive voice.

A. By making the clause itself as the subject in the passive voice.

Examples:

• I hope that he will realize his mistake. (Active voice)
• That his mistake will be realized is hoped by us. (Passive Voice).

• I expected that they would take up the matter. (Active voice)
• That the matter would be taken up by them was expected by me. (Passive Voice).

B. By substituting the clause with pronoun it.

Examples:

• The Romans expected that they would conquer Carthage. (Active voice)
• It was expected by the Romans that Carthage would be conquered by them. (Passive Voice).

• We have learned that you have secured the first rank. (Active voice)
• It has been learned by us that the first rank has been secured by you. (Passive Voice).

Exercises:

• The grandmother was telling her grandchildren an interesting story. (Active voice)
• An interesting story was being told by the grandmother to her grand children. (Passive Voice).
• Her grand children were being told an interesting story by their grandmother. (Passive Voice).

• The postman brought you a parcel. (Active voice)
• A parcel was brought to you by a postman. (Passive Voice).
• You were brought a parcel by the postman. (Passive Voice).

• I have taught the class the first lesson. (Active voice)
• The first lesson was taught by me to the class. (Passive Voice).
• The class was taught the first lesson by me. (Passive Voice).

• The office has sent her a message. (Active voice)
• A message has been sent to her by the office. (Passive Voice).
• She has been sent a message by her office. (Passive Voice).

• The waiter brought us the menu card. (Active voice)
• The menu card was brought to us by the waiter. (Passive Voice).
• We were brought the menu card by the waiter. (Passive Voice).

• They are offering you another chance. (Active voice)
• You are being offered another chance by them. (Passive Voice).
• Another chance is being offered to you by them. (Passive Voice).

• He had told me a lie. (Active voice)
• I had been told a lie by him. (Passive Voice).
• A lie had been told to me by him. (Passive Voice).

• I gave her your message. (Active voice)
• She was given your message by me. (Passive Voice).
• Your message was given to her by me. (Passive Voice).

• Who taught you Sanskrit? (Active voice)
• Sanskrit was taught to you by whom? (Passive Voice).
• You were taught Sanskrit by whom? (Passive Voice).